She said: “At the moment, we believe the condition is ­under-diagnosed because many physicians don’t consider it as a possibility.

“We feel the number of cases diagnosed is far smaller than the real amount of sufferers. Do they ever recover fully? Do they remain at an intermittent level of recovery or is it a ­psychological issue?”

Dr Dawson and her team will carry out MRI scans on sufferers and find out why many can’t ­exercise as much as they should.